Motor vehicle heating system



June 5, 1956 s. H. EDGE 2,749,048

MOTOR VEHICLE HEATING SYSTEM Filed July 27, 1954 Inventor l M A IL M'MW A Horn eys MOTOR VEHICLE HEATING SYSTEM Stanley H. Edge, Lincoln, England, assignor to Clayton Dewandre Company Limited, Lincoln, England, a British company .This invention relates to apparatus for heating the interiors of motor vehicles and particularly to such apparatus of the kind wherein the heat of the water or other liquid coolant in the cooling system of a vehicles engine is utilised for heating air which is delivered to the interior of the vehicle for such purposes as internal heating and de-misting or de-icing of the vehicles wind-screen. Such apparatus usually includes a system of pipes through which liquid flows from the engine-cooling system into one or more heat-exchangers, through which the air to be heated is passed, and back into said cooling system. The flow (hereinafter referred to as the main flow) may be induced either thermosyphonically or by means of a pump.

It is already known to provide vehicle-heating apparatus of this kind with an auxiliary heating system which utilises the heat of the engines exhaust gases to boost the temperature of the liquid flowing into the heat-exchanger, and the object of the present invention is to provide improvements in such apparatus.

According to the invention a vehicle-heating apparatus of the kind described is provided with a booster system which includes means for withdrawing liquid from the engine-cooling system, or from the main flow to the heat-exchanger, passing said liquid into close proximity with the engines exhaust pipe or manifold so as to be heated thereby, and returning the liquid thus heated into the main flow to the heat-exchanger, characterised in that the liquid is returned into said main flow under the control of a thermostatically operated valve which is responsive to the temperature of said liquid and which permits the liquid to be returned into the main flow only after it has attained a predeterminedtemperature, the valve being operable prior to that condition to cause the liquid to be diverted back to the exhaust pipe or manifold so as to be reheated thereby.

Reference will now be made to the accompanying drawing which illustrates diagrammatically an embodiment of the invention.

In this drawing the engine is shown at 1, the radiator at 2, the flow pipe of the engine-cooling system (i. e., the pipe leading from the bottom header of the radiator to the cooling jacket of the engine) at 3, the circulating pump of the cooling system at 4, the return pipe of the cooling system at and the usual thermostatically controlled diverter valve of the cooling system at 6.

The main heating circuit includes a heater 7 through which the air to be heated is passed, a flow pipe 8 leading from the return pipe 5 of the engine-cooling system to the heater, and a return pipe 9 leading from the heater to the flow pipe 3 of the cooling system. More than one heater may be employed if desired.

The booster system includes a tank 10 connected by a pipe 11 With the return pipe 5 of the engine-cooling system and by a pipe 12 with one end of a cylindrical jacket 13 surrounding the engine's exhaust pipe 14. The other end of this jacket is connected by a pipe 15 with a thermostatically operated diverter valve 16 which is responnited States ?atent 6 sive to the temperature of the liquid coming from the jacket and which is in turn connected by a pipe 17 with the main flow pipe 8 leading from the engine-cooling system to the heater. The valve is also connected by a pipe 18 with the tank 10.

In the pipe 12 there is interposed a pump 19 which draws water from the tank and delivers it to the jacket. The tank is supplied from the return pipe 5 of the enginecooling system through the pipe 11. A non-return valve 20'is interposed in the pipe 11 to ensure that none of the water which has been taken into the tank passes back along this pipe.

The water is passed through the jacket by the pump 19, during which passage it is heated by the exhaust pipe, and on to the thermostatically operated diverter valve 16. If the water leaving the jacket is below a predetermined temperature the valve operates to close off the pipe 17 leading into the main heating circuit and open the pipe 18 leading into the tank, so that the water is re-circulated through the jacket to extract further heat from the exhaust pipe. When the water leaving the jacket reaches said predetermined temperature, however, the valve operates to close oft" the pipe 18 and open the pipe 17' so that the water heated by the exhaust pipe is permitted to join the main flow of water to the heater 7 and thereby boost the temperature of said main flow.

Thus, for example, when the engine has just been started, the water which is circulated through the booster system is not permitted to join the main flow of water to the heater until such time as it is hot enough to make an appreciable difference to the temperature of said main flow.

The tank 10 is provided to ensure that an adequate supply of heated water is available from the booster system. Furthermore, any fluctuations which may occur in the temperature of the water entering the booster system from the engine-cooling system are absorbed by the relatively large quantity of water contained in the tank. The latter thus ensures that the temperature of the Water entering the jacket remains fairly even.

In order to ensure that none of the water which has entered the main flow pipe 8 from the booster system passes back along this pipe to the engine-cooling system, a non-return valve 21 is interposed in said pipe between the point at which it leaves the return pipe 5 of the engine-cooling system and the point at which it is joined by the pipe 17 leading from the valve 16.

As an alternative to being connected to the return pipe of the engine-cooling system, the initial intake pipe 11 of the booster system may be connected to the upper part of the engines cooling jacket or to the main flow pipe 8 to the heater 7. The latter alternative is indicated in dot-and-dash lines at 22.

Although the pump 19 is described and shown as being interposed in the pipe connection 12 between the tank and jacket, it can equally well be interposed the pipe connection 15 between the jacket and the diverter valve.

I claim:

1. In a heating apparatus for a motor vehicle having an internal combustion engine and a cooling system and exhaust conduit therefor, the combination of a main heating system having fluid fiow connections with the engine cooling system and including a heat exchanger, a booster system comprising an exhaust heater on the engine exhaust conduit, means including a pump having connections with the inflow of the exhaust heater and the inflow to the main heating system for circulation of liquid through the exhaust heater into the main heating system, and a thermostatic valve interposed between the exhaust heater and the inflow to the main heating system and responsive to a temperature below a predetermined value in liquid in the outflow of the exhaust heater to close I communication between the exhaust heater and the main heating system, and responsive to said predetermined temperature in said liquid to establish communication between the exhaust heater and the main heating system.

2. In a heating apparatus as defined inclaim 1, including a reservoir connected in said booster: system between the inflow to said exhaust heater and said' thermostatic valve.

3. In a heating apparatus for a motor vehicle having an internal combustion engine. and a cooling system and exhaust'conduit therefor, the combination of a main heating system including a heat exchanger and pipes for conducting a main flow of liquid from the engine cooling system to the heat exchanger and backto the engine cooling system, a booster system comprising a tankhaving means for connecting it with the engine cooling system and with the main flow to theheat' exchanger to receive liquid from said cooling system, an exhaust heater mounted on the engine exhaust conduit and having connections with said tank and with said main flow to the heat exchanger, means including a pump interposed in one of said connections, for creating a flow of liquid from said tank through the exhaust heater into the main flow to the heat exchanger, and a thermostatically operated valve interposed in the connection between the exhaust heater and said main flow and responsive to temperature below a predetermined value of liquid discharged from the exhaust heater to cause such liquid to be returned to the exhaust heater for reheating thereby, and operative in response to said predetermined temperature in said liquid from the exhaust heater to cause said liquid to pass into the main flow to the heat exchanger.

4. In a heating apparatus for a motor vehicle having an internal combustion engine and a cooling system and exhaust conduit therefor, the combination of a main heating system comprising a heat exchanger and pipes for conducting a main flow of liquid from the engine cooling system to the heat exchanger and back to the engine cooling system, a booster system comprising an exhaust heater mounted on the engine exhaust conduit and having an upsteam discharge, means including a pump for withdrawing liquid from the engine cooling system and causing such liquid to flow through the exhaust heater for heating such liquid thereby and to deliver the liquid thus heated to the main flow to the heat exchanger, a reservoir interposed in the booster system on the upstream side of the exhaust heater for initially receiving the liquid withdrawn from the engine cooling system, and a thermostatically operated valve interposed in the booster system between the exhaust heater and the main flow to the heat exchanger and responsive to a temperature below a predetermined value of the liquid discharged from the exhaust heater to cause return of such liquid to the exhaust heater for reheating thereby, and responsive to said predetermined temperature to cause delivery of liquid from the exhaust heater to the main flow to the heat exchanger.

5. In a heating apparatus as defined in claim 4, including a non-return valve interposed between said reservoir and the engine cooling system to prevent back-flow of liquid from said reservoir to the engine cooling system.

6. In a heating apparatus for a motor vehicle having an internal combustion engine and a cooling system and exhaust conduit therefor, the combination of a main heating system including a heat exchanger having an inflow connection with the outflow from the engine cooling system and a return connection with the engine cooling system, a booster system comprising an exhaust heater on the exhaust conduit of the engine having an inflow connection with the inflow'to said heat exchanger at a point between the heat exchanger and the outflow from the engine cooling system and a return connection through the heat exchanger to the inflow to the engine cooling system, means including a pump for circulating liquid through the exhaust heater, a non-return valve in the inflow connection to the heat exchanger between the point of connection thereto of the outlet from the exhaust heater and the connection of the inflow connection of the heat exchanger to the outflow of the engine cooling system for preventing back-flow of liquid from the heat exchanger to the outflow from the engine cooling system, and a thermostatic valve interposed between the outflow of the exhaust heater and the inflow connection to the heat exchanger and operative in response to a temperature below a predetermined temperature of liquid in the outflow of the exhaust heater to cause such liquid to return to the exhaust heater for reheating thereby, and responsive to such predetermined temperature of liquid in the outflow of the exhaust heater to establish con-- munication between the outflow from the exhaust heater and the inflow connection to the heat exchanger.

References Cited in the file of this patent UNITED STATES PATENTS 2,072,763 Mayo Mar. 2, 1937 2,208,157 Grutzner July 16, 1940 2,212,250 Schutt Aug. 20, 1940 

